This is a response to a request for applications for a cooperative agreement to carry out a multisite study of multi-modal treatments of ADHD. The overall aim of the proposal is to evaluate the efficacy of drug and psycho-social therapies, and to examine a number of variables that influence treatment response, including other comorbid psychiatric conditions, biological , familial, and environmental risk factors, severity, and diagnostic subtypes. The study is divided into four phases. In Phase 1, the optimal drug and dose for each child is determined on the basis of a 5-week trial of two doses of dextro-amphetamine and methylphenidate (DA and MPH). Patients are randomly assigned to one of 6 possible treatment sequences of DA, MPH, or Placebo (PBO) in a completely counterbalanced double-blind multiple treatment design. Within each of the treatments dosage order (0.3 or 0.8 mg/kg of MPH, or 0. 15 or 0.40 mg/kg DA) is randomized. On the basis of information from 3 domains (home, classroom behavior, academic) a double-blind global judgment is made of the best treatment condition. If side effects (SE) require lower or higher doses than the standard, these are titrated individually after the initial trial. If a patient is a nonresponder on the basis of lack of effect or SE, then individualized psychosocial treatment is continued for the duration of the study. In Phase 2, after the best drug choice is established, the patients are randomized to 5 psychosocial conditions: Parent training, Social Skills/Cognitive, Educational Consulting, and Individualized Management combination (IM), or None. These are divided between two ADHD subtypes: ADHD and U-ADD (ADDnoH). Treatments are monitored with instruments specific to each treatment as well as some general symptomatic measures. In Phase 3 drug is withdrawn for 1 month or added to those who received PBO previously. This phase examines the effect of drug treatment order on psychosocial treatment and the effect of withdrawal of medication. After this month Phase IV is a 6-month followup period in which regular monitoring is used to measure relapse. Treatment generalization over time and duration of effects are measured by survival analysis methods. Comorbidity and risk factors are evaluated by regression analysis at each phase.